Soontornpas, C., R. Soontornpas, and P. Chumworathayi. “Work Measurement by Work Sampling Technique in Department of Pharmacy Service”. Srinagarind Medical Journal, vol. 23, no. 1, Nov. 2013, pp. 45-52, https://li01.tci-thaijo.org/index.php/SRIMEDJ/article/view/13052.